package site.qianli.discover.common.util;

public class VersionUtil {

    public static void main(String[] args) {
        System.out.println(beforeVersion("6.2.0", "5.3.0"));
        System.out.println(beforeVersion("5.3.0", "5.3.0"));
        System.out.println(beforeVersion("4.3.0", "5.3.0"));
    }


    public static boolean beforeVersion(String thisVersion, String beforeVersion) {
        int result = compareVersion(thisVersion, beforeVersion);
        return result >= 0 ? false : true;
    }

    /**
     * 比较版本号的大小,前者大则返回一个正数,后者大返回一个负数,相等则返回0
     *
     * @param version1
     * @param version2
     * @return
     */
    public static int compareVersion(String version1, String version2) {
        String[] versionArray1 = version1.split("\\.");
        String[] versionArray2 = version2.split("\\.");
        int idx = 0;
        int minLength = Math.min(versionArray1.length, versionArray2.length);//
        // 取最小长度值
        int diff = 0;
        while (idx < minLength && (diff = versionArray1[idx].length() - versionArray2[idx].length()) == 0// 先比较长度
                && (diff = versionArray1[idx].compareTo(versionArray2[idx])) == 0) {//
            // 再比较字符
            ++idx;
        }
        // 如果已经分出大小，则直接返回，如果未分出大小，则再比较位数，有子版本的为大；
        diff = (diff != 0) ? diff : versionArray1.length - versionArray2.length;
        return diff;
    }
}
